Completion and working over of wells



May I, 1962 w. M. OREILLY COMPLETION AND WORKING OVER 0F WELLS 3Sheets-5heet 1 Filed Oct. '7, 1959 11:! V EN TOR.

WALLACE M. O'REILLY,

y 1, 1962 w. M. O'REILLY 3,032,104

COMPLETION AND WORKING OVER 0F WELLS Filed Oct. 7, 1959 5 Sheets-Sheet2.

FIG. 5.

I I VV ENTOR. WALLACE M. O'REILLY,

ATR

May 1, 1962 w. M. OREILLY COMPLETION AND WORKING OVER 0F WELLS 5Sheets-Sheet 3.

Filed Oct. 7, 1959 F IG. 8.

INVENTOR.

WALLACE M. O'REILLY,

ATTORNE Y.

3,032,104 COMPLETION AND WORKING OVER OF WELLS Wallace M. OReilly,Midland, Tex., assignor, by mesne assignments, to Jersey ProductionResearch Company, Tulsa, Okla., a corporation of Delaware Filed Oct. 7,1959, Ser. No. 845,005 7 Claims. (Cl. 166-35) The present invention isdirected to a method for cornpleting and working over a well. Morespecifically, the invention is concerned with the completion and workingover of wells penetrating a plurality of hydrocarbon productive zones.In its more specific aspects, the invention is directed to completingand working over of wells for simultaneous and separate production froma plurality of hydrocarbon productive zones.

The present invention may be briefly described as a method forcompleting and working over a well having a first pipe string arrangedtherein extending to a lower hydrocarbon productive zone spaced below anupper hydrocarbon productive zone. The well has an eccentric second pipestring which is fluidly connected at its lower end to the first pipestring at a point between the two zones. The two zones are separatelyperforated and the perforated zones are isolated from each other abovethe point of fluid interconnection for separate production ofhydrocarbons from each of the zones. The lower zone may be perforatedfirst and then the two zones are isolated from each other and the upperzone is then perforated last. The production from the upper zoneproceeds upwardly through the first pipe string and production from thelower zone proceeds upwardly through the second pipe string.

One of the zones is isolated from the other of the zones when it isdesired to work over the one zone and a workover fluid such as acementitious material, stimulating agents such as hydrochloric acid,surface active agents, and plastics, consolidating agents, and the likeare flowed down the first pipe string to the first zone and any excessis removed up the second pipe string with fluid in the well beingdisplaced up the second pipe string.

It is contemplated in the practice of the present invention that theupper zone may be isolated from the first pipe string and a workoverfluid flowed down the first pipe string and up the second pipe stringfor Working over the lower zone. It is also contemplated that the zonesmay be isolated below the point of fluid interconnection and a workoverfluid flowed down the first pipe string and up the second pipe string towork over the upper zone. It is further contemplated that whennecessary, the two zones may be isolated above the point of fluidinterconnection and the two zones separately pumped to producehydrocarbons to exhaustion of the two zones.

In the practice of the present invention, the first pipe string is ofsuch diameter that all tools may be lowered downwardly therethroughwhile the second pipe string is of such diameter sufiicient to conductfluids to the wellhead. It is further contemplated in the practice ofthe present invention that the first pipe string will be reduced indiameter from a point just above the point of fluid interconnection toits greatest depth in the well.

The diiference in diameters of the upper and lower portions of the firstpipe string will permit easy passage in the upper portion for toolshaving sealing elements (packers) or holding elements such as slips ordogs which may require a closer fit in the lower portion where they willbe employed. The same end result may be accomplished by using a singlesized string equipped with seating and/or sealing nipples having fixeddiameters which are positioned to become increasingly smaller toward thebottom of the hole.

States ateht ice The present invention will be further illustrated byreference to the drawing in which:

FIGS. 1 to 6, inclusive, are a stepwise illustration in partial sectionof apparatus for practicing a preferred mode of the present invention;

FIGS. 7a and 7b are elevational views partly in section of a pump toolsuitable for use in the present invention; and

FIG. 8 is a sectional view taken along the line 8--8 of FIG. 7a.

Referring now to the drawing and particularly to FIGS. 1 to 6 in whichidentical numerals will be employed to designate identical parts,numeral 11 designates a borehole drilled from the earths surface, notshown, to penetrate a plurality of hydrocarbon productive zones 12 and13 which are vertically spaced apart. Arranged in the well bore 11 is afirst pipe string 14 which extends from the wellhead, not shown, atleast into the hydrocarbon productive zone 13. Connected into pipestring 14 at a point between the hydrocarbon productive zones 12 and 13is a second pipe string 15 which is of smaller diameter than the pipestring 14. It is to be noted that the lower section 16 of the pipestring 14 is of lesser diameter than the upper section 17.

At spaced apart points in the pipe string 14 are suitable supportingmeans 18, 19, 20, 21, and 22. Supporting means 18 and 19, which willsuitably be landing nipples or other anchoring or suspending means, aredesigned to support various completion and servicing elements as will bedescribed further. A suitable landing nipple is described in theComposite Catalog of Oil Field Equipment and Services, 1958-59 ed., vol.3, p. 3971. Lowered into the pipe string 14 on a wire line 23 is aperforator 24 which suitably may be a bullet gun perforator, a shapedcharge perforator, or a mechanical or chemical perforator. Theperforator 24 is operated in zone 13 to form perforations 25 from thepipe string 14 into the zone 13, the perforations 25 penetratingcementitious material 26 such as Portland cement which cements the pipestrings 14 and 15 in the borehole 11.

After the perforations 25 have been made through the cement 26 and intothe zone 13, the perforator 24 is withdrawn through the pipe string 14and a suitable wireline plug or barrier member 27 may be placed on thelanding nipple 20 and sealed therein by lowering the barrier member 27on a wire line. A suitable barrier member is described in Serial No.769,343, new Patent No. 2,966,946 filed October 24, 1958, entitledApparatus for Use in a Well Bore. Thereafter a perforator such as 28 islowered on wire line 23 and suitably oriented by orienting means 29 suchthat its operative surface is positioned in a direction away from thepipe string 15 and such that only the pipe string 14 will be penetrated.An orienting means suitable for practice of the present invention isdescribed in Ser. No. 756,666, filed August 22, 1958, entitled AlignmentMeans for Perforating Multi-Pipe String Wells. After perforations havebeen made in zones 12 and 13, hydrocarbon production may be suitably hadfrom the two zones as shown most clearly in FIG. 3, the production fromthe upper zone proceeding through perforations 30 into the pipe string14 to the wellhead while production from the perforations 25 proceeds tothe wellhead through pipe string 14 and then through pipe string 15 tothe wellhead, the barrier 27 preventing comingling of flow from the twoformations.

When it is desired to workover the two zones and particularly the lowerzone 13, a first tubular conduit 31 is lowered through the pipe string14 and sealingly suspended therein in landing nipples 19 and 20 suchthat the perforations 30 are completely blanked off and flow from theperforations 30 into the pipe string 14 is terminated, seals 19:: and20a being provided on the exterior of tubular conduit 31 for effectingthe seal. Sealingly suspended within the tubular member 31 is a secondtubular member 32 having its upper end sealed by sealing means 33 in thelower end of the tubular member 31. This tubular member 32 is ofsuflicient length to extend below the fluid interconnection between thepipe strings 14 and 15 and to extend to within or adjacent to the lowerzone 13. Workover fluids may now be flowed downwardly through the pipestring 14 and into the lower zone 13. For example, cementitiousmaterial, consolidation agents, stimulating agents, and the like may beflowed downwardly through the pipe string 14 and into zone 13 and anyexcess removed upwardly through the annulus 34 into the pipe string 15to the well head. Any fluid in the pipe string 14 would be displacedlikewise up the pipe string 15. Of course, it is realized that if thezone 13 is cemented to fill the perforations 25, it may be necessary toreperforate in the zone 13, or into either zone, or between the zone 12and the zone 13, or in a zone lower than the zone 13 if the pipe stringextends a sufficient distance below, as is contemplated in the presentinvention.

Thereafter the tubular conduits 31 and 32 may be removed and productionresumed by placing a barrier member such as 27 on the landing nipple toisolate the two zones.

When it is desired to workover the upper zone 12, a barrier member orplug such as may be lowered on a wire line such as 23 and placed on thelanding nipple 22 to close off flow from the zone 13 through theperforations 25. Thereafter, a workover fluid which may be a stimulatingagent may be flowed down the pipe string 14 with any excess or displacedfluid proceeding upwardly to the wellhead through the pipe string 15.After the workover operation has been completed, the barrier or plugmember 27 may be again placed on the landing nipple 20 and productionresumed from the two zones, the barrier member 35 having been removed.

Under circumstances where the zones 12 and 13 lose their ability to flowthrough natural means, as shown in FIG. 6, a suitable pump tool 36containing rod pumps may be located in the pipe string 14. The rod pumpsare connected to, and reciprocated by, a sucker rod 38 extending to asuitable pumping unit at the earths surface, not shown. By reciprocationof the rod 38, production is again had simultaneously through the pipestrings 14 and 15 to the wellhead. The details of pump tool 36 areillustrated in FIGS. 7a and 7b.

Referring now to FIGS. 7a and 7b, there is shown a pump tool 36comprising an elongated pump housing 40 provided with upper and lowerpumping assemblies 41 and 42 interconnected by means of a rod 43.Housing 40 is provided with suitable seals 44, 45, and 46 to isolateproduction from the two zones 12 and 13. The lower end of housing 40extends to within or adjacent the lower zone 13 and may suitably belatched in lower section 16 of tubing string 14 by means of a bottomhold-down latch 47 arranged in an annular recess 48.

Upper pump assembly 41 includes a pump plunger 49 slidably arranged in achamber 50 in housing 40. Pump plunger 49 is provided on its upper andlower ends with ball check valves 51 and 52, respectively, to permitpassage of fluid into and out of plunger 49 as it reciprocates inchamber 50. Arranged below plunger 49 is an annular wall member 53having formed therein a plurality of passageways 54 each provided with aball check valve 55. Wall member 53 is also provided with a bore 56through which connecting rod 43 may extend. A second annular wall member57 positioned below wall member 53 forms a chamber 58 within housing 40.Chamber 58 is provided with ports 59 for fluid communication withproduction zone 12. Wall member 57 has formed therein a bore 60 providedwith seals 61 to sealingly engage rod 43 which extends therethrough.

Lower pump assembly 42 includes a pump plunger 62 slidably arranged in achamber 63 in pump housing 40.

Pump plunger 62 is provided on its upper and lower ends with ball checkvalves 64 and 65, respectively, to permit passage of fluid into and outof plunger 62 as it reciprocates in chamber 63. As can be seen in thedrawing, housing 40 is provided with a lower pump standing valve 66which may be a ball check valve to permit fluid flow into chamber 63.

In operation as the sucker rod 38 is reciprocated fluid from lower zone13 is pumped through check valve 66, plunger 62, port 67, and port 68upwardly through pipe string 15. Production from upper zone 12 is pumpedthrough check valve 55, plunger 49, port 69, and port 70 upwardlythrough pipe string 14 with the seals 45 and 61 isolating productionfrom the zones 12 and 13.

It is to be noted that the pump tool 36 is placed in a common housing tofacilitate installation and removal from the well.

The present invention is of considerable importance and utility in thatit is possible to produce simultaneously and separately from two zonesand yet workover the two zones by lowering tools only through one pipestring while providing a plurality of pipe strings for conducting offluids from the one pipe string through which completion andworking-over is performed. A minimum of equipment is required and alloperations are conducted by wireline.

The nature and objects of the present invention having been completelydescribed and illustrated, what I wish to claim as new and useful andsecure by Letters Patent is:

1. In a well having a first pipe string arranged therein extending atleast to a lower hydrocarbon productive Zone spaced below an upperhydrocarbon productive zone and having an eccentric second pipe stringfluidly connected at its lower end to the first pipe string at a pointbetween said two zones, the method which comprises sepa ratelyperforating the upper and lower zones from within the first pipe string,isolating said zones from each other above said point and below theupper productive zone and separately obtaining production from each ofsaid zones, production from the upper zone proceeding upwardly throughthe first pipe string and production from the lower zone proceedingupwardly through the second pipe string, isolating one of said zonesfrom the pipe string through which said one zone is produced, andflowing fluid down the first pipe string to the other of said zones andremoving any excess fluid up the second pipe string.

2. In a well having a first pipe string arranged therein extending to alower hydrocarbon productive zone spaced below an upper hydrocarbonproductive zone and having an eccentric second pipe string fluidlyconnected at its lower end to the first pipe string at a point betweensaid two zones, the method which comprises separately perforating theupper and lower zones from within the first pipe string, isolating saidzones from each other above said point and below the upper productivezone and separately obtaining production from each of said zones,production from the upper zone proceeding upwardly through the firstpipe string and production from the lower zone proceeding upwardlythrough the second pipe string, isolating said upper zone from saidfirst pipe string and flowing fluid down the first pipe string to thelower zone, and removing any excess fluid up the second pipe string.

3. In a well having a first pipe string arranged therein extending to alower hydrocarbon productive zone spaced below an upper hydrocarbonproductive zone and having an eccentric second pipe string fluidlyconnected at its lower end to the first pipe string at a point betweensaid two zones, the method which comprises separately perforating theupper and lower zones from within the first pipe string, isolating saidzones from each other above said point and below the upper productivezone and separately obtaining production from each of said zones,production from the upper zone proceeding upwardly through the firstpipe string and production from the lower zone proceeding upwardlythrough the second pipe string, isolating said lower zone from saidsecond pipe string, and flowing fluid down the first pipe string to theupper zone, and removing any excess fluid up the second pipe string.

4. In a well having a first pipe string arranged therein extending to alower hydrocarbon productive zone spaced below an upper hydrocarbonproductive zone and having an eccentric second pipe string fluidlyconnected at its lower end to the first pipe string at a point betweensaid two zones, the method which comprises separately perforating theupper and lower zones from within the first pipe string, isolating saidzones from each other above said point and below the upper productivezone and separately obtaining production from each of said zones, production from the upper zone proceeding upwardly through the first pipestring and production from the lower zone proceeding upwardly throughthe second pipe string, isolating said upper zone from said first pipestring, flowing a workover fluid down the first pipe string to the lowerzone and removing any excess workover fluid up the second pipe string,re-establishing communication between said upper zone and said firstpipe string, isolating said lower zone from said second pipe string, andthen flowing a workover fluid down the first pipe string to the upperzone and removing any excess workover fluid up the second pipe string.

5. In a well having a first pipe string arranged therein extending to alower hydrocarbon productive zone spaced below an upper hydrocarbonproductive zone and having an eccentric second pipe string fluidlyconnected at its lower end to the first pipe string at a point betweensaid two zones, the method which comprises separately perforating theupper and lower zones from within the first pipe string, isolating saidzones from each other above said point and below the upper productivezone and separately obtaining production from each of said zones,production from the upper zone proceeding upwardly through the firstpipe string and production from the lower zone proceeding upwardlythrough the second pipe string, isolating said upper zone from saidfirst pipe string and flowing a workover fluid down the first pipestring to the lower zone and removing any excess workover fluid up thesecond pipe string, re-establishing communication between said upperzone and said first pipe string, isolating said lower zone from saidsecond pipe string, and flowing a workover fluid down the first pipestring to the upper zone and removing any excess workover fluid up thesecond pipe string, re-establishing communication between said lowerzone and said second pipe string, then again isolating said zones fromeach other above said point and below the upper productive zone andseparately pumping hydrocarbons from said zones.

6. In a well having a first pipe string arranged therein extending to alower hydrocarbon productive zone spaced below an upper hydrocarbonproductive zone and having an eccentric second pipe string fluidlyconnected at its lower end to the first pipe string at a point betweensaid two zones, the method which comprises separately perforating theupper and lower zones, isolating said zones from each other above saidpoint and below the upper productive zone and separately obtainingproduction from each of said zones, production from the upper zoneproceeding upwardly through the first pipe string and production fromthe lower zone proceeding upwardly through the second pipe string,isolating one of said zones from one of said pipe strings and flowing awork over fluid down the first pipe string to the other of said zonesand removing any excess workover fluid up the second pipe string, saidzones being separately perforated by lowering a perforator through thefirst pipe string and operating it first in the lower zone and then inthe upper zone.

7. A method in accordance with claim 6 in which said zones are isolatedabove said point and below the upper productive zone after the lowerzone is perforated.

References Cited in the file of this patent UNITED STATES PATENTS2,642,803 Morris et a1 June 23, 1953 2,760,578 Tausch Aug. 28, 19562,911,048 Dublin et a1. Nov. 3, 1959 2,935,131 McCune May 3, 1960

